Re-Textured Items
Those are Undynes Spear (Trident), DETERMINATION (Outdated) and a tasty Cinnamon Butterscotch Pie (Pumpkin Pie)
Custom Death Message + Screen
One of the many Custom Death Messages and the new Death Screen
Determination
The Re-Textured Totem of Undying and the advancement you get for it
Elytra with Delta Rune Symbol
The Elytra Texture now has the Delta Rune Symbol on it
Slash
The red Slash from Undertale when you hit a Monster
Shield Texture
Delta Rune Symbol on the Shield (Does not affect Shields with Banner)
Load Failed
When the bed is obstructed this message comes up